期刊
JOURNAL OF BIOLOGICAL CHEMISTRY
卷 282, 期 8, 页码 5201-5206出版社
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
DOI: 10.1074/jbc.M611665200
关键词
-
资金
- NIGMS NIH HHS [GM33063] Funding Source: Medline
Human xylosyltransferase I (XT-I) initiates the biosynthesis of the glycosaminoglycan (GAG) linkage tetrasaccharide in proteoglycans. Xylosyltransferase 11 (XT-II) is a protein homologous to XT-I but with hitherto unknown activity or physiological function. Here, we report the enzymatic activity of XT-II and provide evidence that XT-II initiates the biosynthesis of both heparan sulfate and chondroitin sulfate GAGs. Transfection of the xylosyltransferase-deficient Chinese hamster ovary mutant pgsA-745 with XT-I or XT-II coding cDNA completely restored GAG biosynthesis. GAG disaccharide analysis revealed that XT-I- and XT-II-transfected pgsA-745 cells produced similar amounts of chondroitin sulfate and heparan sulfate. Furthermore, a high xylosyltransferase activity was measured after transfection with cDNAs encoding either isozyme. Analysis of the enzyme activity revealed that XT-II catalyzes the transfer of xylose to similar peptide acceptors as XT-I but with different efficiency. The optimal XT-II acceptor was observed using a bikunin-related peptide (K-m 5.2 mu m). Analysis of XT-I and XT-II mRNA expression in murine tissues showed a differential expression pattern for both enzymes. In particular, XT-II is highly expressed in liver tissue, where XT-I transcripts were not detected. This is the first report on the enzyme activity of XT-II and its involvement in chondroitin sulfate and heparan sulfate biosynthesis.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据